Various work machines include work implements that are raised and lowered to perform desired tasks. For example, skid steer loader work machines may include a bucket that is raised and lowered to assist in transferring material between desired locations. In many cases, such work implements are coupled to a frame of a work machine by a lift boom assembly that serves to control the movement of the work implement between the lowered and raised positions. Conventional lift boom assemblies include a boom directly coupled to a frame of the work machine by a single pivot connection. This single pivot connection causes the work implement to travel along an arcuate path between the raised and lowered positions. In particular, when the boom starts to raise, there is forward movement of the work implement and, after the boom goes over center, there is a substantial amount of upward and rearward movement of the work implement. This lift path has the drawback of shortening the forward reach of the work implement when the boom is in the raised position.
Attempts have been made to overcome this drawback associated with the arcuate lift path of boom assemblies having a single pivot connection to the work machine frame. For example, U.S. Pat. No. 6,616,398 issued to Brian Dershem, et al. discloses a boom assembly including a boom coupled to each side of a frame of a work machine by a pair of linkages and an actuator. While the boom assembly lift path provided by the disclosed linkage arrangement of the '398 patent may be improved over the lift path of the single pivot boom assembly, as illustrated in FIG. 1 of the '398 patent, the lift path still maintains an arcuate movement between the raised and lowered positions. In addition, the linkage arrangement of the '398 patent may require a greater force than desired to initiate movement of the boom assembly.
The present invention is directed to overcoming one or more of the problems set forth above.